KR20010114177A - Poly(arylene ether) adhesive compositions - Google Patents

Abstract

Adhesives for thermoplastic films are made from compositions comprising blends of poly (arylene ether), thermosetting resins, reinforcing agents, optional plasticizers, and curing agents. Such adhesives have been found to be particularly useful in circuit board products.

Description

Poly (arylene ether) adhesive composition {POLY (ARYLENE ETHER) ADHESIVE COMPOSITIONS}

The present invention relates to an adhesive composition for thermoplastic substrates and a method for producing the same. More particularly, the present invention relates to an adhesive composition comprising a poly (arylene ether) polymer.

There is a continuing need in the art for thermoset adhesives for use with substrates used in connection with thermoplastic adhesives, particularly prefabricated printed circuit boards. The need to miniaturize circuit boards has increased and methods such as the incorporation of microvias in printed circuit boards have been developed. Moreover, it is advantageous to have a substrate capable of microbias technology and to be drilled laser without the insertion of reinforcing agents such as woven or cut glass fibers.

In the assembly of printed circuit boards it is known to use copper foil coated with an adhesive, or to use a copper foil coated with an adhesive and then partially cured with a cured adhesive as described in US Pat. No. 5,557,843. This method is limited by the thickness of the copper foil that is effectively coatable and handleable for practical use in printed circuit boards or rigid-flex plates. Thermoplastic films are known which are metallized with copper or other conductive material to be as thin as 3 microns or 5 microns. Examples of metallized polyimides are described, for example, in US Pat. Nos. 4,842,946 and 4,959,121. These metallized films can be coated with an adhesive and used for example in microbias and rigid-flex articles.

Thermoplastic adhesives, in particular adhesives suitable for bonding circuit boards, need to have good solvent resistance, stiffness and adhesion. Partially cured substrates used in the manufacture of circuit boards must have minimum flow properties, crack resistance, and the ability to exhibit adequate bond strength to all adhesives during curing to provide adequate flow and filling. When used with circuit boards, the adhesive includes a thermoplastic film, copper and / or copper treated to improve bonding, and other resin plastic substrates used in the circuit board. When used in printed circuit boards, the dielectric loss and expandability of the adhesive should be adjusted to closely match the dielectric loss and expandability of the substrate. U. S. Patent No. 3,900, 662 to Yuan discloses an acrylic adhesive, but such adhesives have high expansion values at relatively low glass transition temperatures and soldering temperatures. Thermoset poly (arylene ether) resin compositions have many desired properties, but low molecular weight poly (arylene ether) useful for penetration of reinforcing materials are vulnerable in partially cured form, while high molecular weight poly (arylene ether) Due to the high viscosity it is difficult to form the film at room temperature and tends to be vulnerable in the partially cured form. US Pat. No. 4,853,423 to Walles discloses poly (arylene ether) resins and polyepoxy resins with novolak resins on circuit boards. More recent patents on poly (arylene ether) resins, such as US Pat. No. 5,834,565 to Tracy et al., Disclose the use of poly (arylene ether) polymers in circuit board based materials having a number average molecular weight of less than about 3,000. The use is disclosed. Commercial poly (arylene ether) resins have a number average molecular weight ranging from about 15,000 to about 25,000. Although the cured clear films of these compositions are tough, partially cured or B-staged products tend to be fragile. Thus there remains a need in the art for improved and less fragile thermosetting adhesives for use with thermoplastic compositions.

In the most common form, the present invention is intended for use with thermoplastic adhesives comprising poly (arylene ether) resins, thermosetting resins, optional reinforcing agents, curing agents, and optional plasticizers having a number average molecular weight of about 8,000 to about 13,000. It may be described as a curable thermosetting adhesive composition. In use, the compositions can be blended, applied to the substrate to be bonded, partially cured or dried, and the substrate can then be connected to another adhesive to fully cure.

The curable thermosetting adhesive composition is an optional reinforcing agent, curing agent, and selection compatible with poly (arylene ether) resins, thermosetting resins, poly (arylene ether) resins and thermosetting resins having a number average molecular weight ranging from about 8,000 to about 13,000. Contains plasticizers.

In an advantageous feature, the composition can be blended, applied to the substrate to be bonded, partially cured, and then fully cured by connecting the substrate to another adhesive. Suitable bond strengths are made between thermoplastic base materials, conductive metals such as copper and other thermoset base circuit board materials.

The present invention relates to an adhesive resin composition having better processability, showing reduced B-step (partially cured step) frictional performance and minimal flow during lamination. Specifically, compositions comprising poly (arylene ether) and thermosetting resins are applied to thermoplastic substrates that may have an electrically conductive metal, such as copper, on one side. Thermosetting resins are polymers that form a network of three-dimensionally crosslinked polymer chains that cannot be softened or reheated for additional use. Before they are crosslinked, the thermosetting resin must contain sufficient reactive functional groups to form a three-dimensional network while flowing and curing. General groups of thermosetting resins include, for example, epoxy, phenolic, alkyd, acrylate, polyester, polyimide, polyurethane, bis-maleimide, cyanate esters, vinyl, benzocyclobutene resins and benzoxazines. These compositions may further comprise various catalysts, flame retardants, and other components, as desired. The thermosetting components, such as those described above, may be used alone or in combination with one another or with other thermoplastic resins. Suitable thermoplastic reinforcing material substrates such as thermoplastic polyimide, polyetherimide, polyesteretherimide, blends of poly (arylene ether) and polyimide, and used to coat blends of poly (arylene ether) and polyester In these cases, they provide miscible substrates that are particularly applicable to making laminated articles suitable for articles such as printed circuit boards, rigid-flex circuit boards or any other article having good dielectric properties as desired. Prior to crosslinking, the composition is gelled at room temperature, while the composition dissolved in an organic solvent such as toluene at high temperature is shear strained to a liquid, which promotes the coating of the substrate at room temperature. The cured adhesive layer material prepared from the composition is high in solder resistance, solvent resistance, moisture resistance and flame retardancy. In addition, the cured material has good dielectric and dimensional stability at high temperatures.

Poly (arylene ether) resins having conventional structures can be applied to blends comprising multiple structural units of formula

Where

Q ¹ independently represents halogen and oxygen atoms by halogen, such as primary or secondary lower alkyl, phenyl, haloalkyl, aminoalkyl, hydrocarbonoxy, or two or more carbon atoms containing up to 7 carbon atoms. Isolated halohydrocarbonoxy;

Q ² is independently hydrogen, halogen, primary or secondary lower alkyl, phenyl, haloalkyl, hydrocarbonoxy, or halohydrocarbonoxy wherein the halogen and oxygen atoms are separated by two or more carbon atoms.

Examples of suitable primary lower alkyl groups are methyl, ethyl, n-propyl, n-butyl, isobutyl, n-amyl, isoamyl, 2-methylbutyl, n-hexyl, 2,3-dimethylbutyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl and the corresponding heptyl group. Examples of secondary lower alkyl groups are isopropyl, secondary-butyl and 3-pentyl. Preferably, any alkyl radical is straight rather than branched. Preferably, each Q ¹ is alkyl or phenyl, in particular C ₁ to C ₁₄ alkyl, each Q ² is hydrogen.

Both homopolymerized and copolymerized poly (arylene ether) polymers are included. Preferred homopolymers are those containing 2,6-dimethylphenylene ether units. Suitable copolymers are, for example, random copolymers containing these units together with 2,3,6-trimethyl-1,4-phenylene ether units or copolymerization of 2,6-dimethylphenol and 2,3,6-trimethylphenol. Copolymers derived from. In addition, poly (arylene ether) polymers containing residues prepared by grafting polymers such as vinyl monomers or polystyrene, and binders such as low molecular weight polycarbonates, quinones, heterocycles and foams are known, Also included are poly (arylene ether) polymers, which are high molecular weight polymers produced by reaction with the hydroxyl groups of the arylene ether) chain. The poly (arylene ether) polymer in the composition further comprises any of the above combinations. Many suitable random copolymers as well as homopolymers are disclosed in the patent literature. U.S. Patents 4,054,553, 4,092,294, 4,477,649, 4,477,651, and 4,517,341 are incorporated herein by reference.

Typically poly (arylene ether) resins are prepared by oxidative bonding of one or more monohydroxyaromatic compounds, such as 2,6-xylenol or 2,3,6-trimethylphenol. Generally catalyst systems are used for such bonding. Typically they usually comprise one or more heavy metal compounds such as copper, manganese or cobalt compounds with various other materials.

Particularly useful poly (arylene ether) resins have a number average molecular weight of about 8,000 to about 13,000, more preferably about 9,000 to about 12,000, most preferably about 10,000 to about 11,000 as determined by gel permeation chromatography. It has a hydroxy group. Thus poly (arylene ether) resins have an intrinsic viscosity (I.V.) of about 0.20 to about 0.40 dl / g, preferably about 0.28 to about 0.32 dl / g, as measured in chloroform at 25 ° C. Such poly (arylene ether) can be obtained by direct synthesis or by redistribution of poly (arylene ether). Suitable methods for redistribution are described, for example, in US Pat. No. 5,834,565. In one procedure, low molecular weight poly (arylene ether) may be prepared from poly (arylene ether) having a number average molecular weight, typically in the range of about 15,000 to 25,000. The preparation of such low molecular weight poly (arylene ether) resins can be accomplished by reacting the poly (arylene ether) resins with oxidants such as peroxides or quinones with or without phenols (including bisphenols). Another process is to obtain a low molecular weight poly (arylene ether) resin by oxidative bonding, as described above, to produce a resin of the desired number average molecular weight, which is preferably isolated by a direct isolation method. However, even such low molecular weight resins can be selectively functionalized with peroxides or peroxides and phenols, resulting in even lower molecular weights.

Phenolic systems useful in the redistribution reactions described herein include all known phenolic compounds, including those exemplified by Formula 2:

Where

A ¹ is any aromatic, mixed aliphatic aromatic hydrocarbon, heterocycle or similar derivative thereof;

X is a hydroxyl group residue;

n is any integer from 1 to about 10, preferably from 1 to about 5.

In general, any peroxide, including those described in Formula 3, may be useful in a redistribution reaction:

A ² -OOA ³

Where

A ² and A ³ are any aliphatic acyl groups, aromatic acyl groups, alkyl or mixed aliphatic aromatic hydrocarbons, hydrogen or inorganic ester residues or similar derivatives thereof.

Typical peroxides include, without limitation: 1) diacyl peroxides, such as dibenzoyl peroxide, 4,4'-di-tert-butylbenzoyl peroxide or other aryl substituted derivatives, dilauryl peroxide, acetyl benzoyl peroxide, Acetyl cyclohexylsulfonyl peroxide and diphthaloyl peroxide; 2) peroxydicarbonates such as dicetylperoxydicarbonate; 3) Peroxide acids such as perbenzoic acid, 3-chloroperbenzoic acid, 4-nitroperbenzoic acid, and other substituted derivatives of perbenzoic acid, peroxyacetic acid, peroxypropanoic acid, peroxybutanoic acid, peroxynonanoic acid, peroxydodecane Acids, diperoxyglutaric acid, diperoxyadipic acid, diperoxyoctanediionic acid, diperoxynonanediionic acid, diperoxydecanediionic acid, diperoxydodecanedioic acid, monoperoxyphthalic acid, and inorganic acids such as sulfuric acid peroxide, Disulfide peroxide, phosphate peroxide, diphosphate peroxide and their corresponding salts; And 4) peroxycarboxyl esters such as tert-butyl performate, tert-butyl peracetate, tert-butyl peroxyisobutyrate, tert-butyl perbenzoate, cumyl perbenzoate, tert-butyl perth Oxynonanoate, tert-butyl monoperoxymaleate, tert-butyl monoperoxyphthalate, di-tert-butyl diperoxy adipate, and 2,5-dimethyl 2,5-bis (benzoylperoxy Hexane.

These peroxides can be used alone or together in the presence or absence of a catalyst that induces decomposition of the peroxide and increases the rate of radical production. Other oxidants known in the art, including quinones such as 2,2 ', 6,6'-tetramethyl diphenoquinone (TMDQ), can be used with or without phenol.

Typically poly (arylene ether) resins comprise from about 5 to about 50 weight percent, preferably from about 20 to about 40 weight percent, most preferably from about 25 to about 35 weight percent of total adhesive composition solids.

The adhesive composition further comprises a thermosetting resin in its monomeric, oligomeric or polymeric state and comprises the reaction products of curing agents and catalysts known in the art. Examples of such thermosetting resins include epoxy, phenolic, alkyd, allyl, polyester, polyimide, polyurethane, bis-maleimide, cyanate esters, vinyl, benzoxazine and benzocyclobutene resins. Mixtures of two or more thermosetting resins may also be used with or without addition of a curing agent or catalyst to produce polyphenylene ether thermosetting resins. Preferred thermosetting resins are epoxides or phenols and mixtures thereof, such as 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) or bis (2-hydroxyphenyl) methane (bisphenol F), or these epoxy And partial condensation products of bisphenols. Preferably the thermosetting resin composition as used herein, whether components or reactants, comprises at least one bisphenol polyglycidyl ether. The bisphenolpolyglycidyl ethers preferably used may be halogen free or may be a mixture of halogen-free and halogen-containing (preferably halogen substituent is bromine) polyglycidyl ethers. The total amount of bromine may be about 10 to about 30 weight percent based on the weight of the solid resin composition.

Preferred thermosetting resin compositions include phenols such as epoxides or bisphenol A and mixtures of epoxides or partial condensation products of epoxy and bisphenols. As used herein, thermosetting resin compositions, whether components or reactants, preferably comprise one or more bisphenol polyglycidyl ethers. The bisphenol polyglycidyl ethers preferably used may be halogen-free or may be a mixture of halogen-free and halogen-containing (preferably halogen substituents are bromine) polyglycidyl ethers. The total amount of bromine may be about 10 to about 30 weight percent.

Epoxide components useful in the present invention may, in a broad sense, include any epoxy compound. Suitable epoxy components useful in this formula include Formula 4:

Where

A ⁴ is any aromatic, aliphatic, mixed aliphatic aromatic hydrocarbon, heterocycle or similar derivative thereof;

X is an epoxy containing moiety;

n is preferably any integer of 1 to 100.

When using epoxides, at least two epoxy compounds that are brominated to provide flame retardancy and another epoxy compound at a level sufficient to provide a total bromine content of from about 10 to about 30 weight percent based on the weight of the solid composition Preference is given to epoxides containing epoxy compounds. Preferred epoxy compounds include those in which n is 1 to 4, more preferably n is 2.

Typical substances in this class are:

1) a diepoxide exemplified by the following formula (5):

Where

A ⁵ and A ⁶ are aromatic radicals;

Y is a single bond or a crosslinking radical.

The A ⁵ and A ⁶ radicals may be unsubstituted or substituted with typical groups selected from aryl, alkyl, alkoxy, halogen and the like. Y may include crosslinking radicals such as alkylene, cycloalkylene, arylene, oxy, thio, sulfonyl, sulfoxy and carbonyl.

The most common examples of compounds described in Formula 5 include diglycidyl ethers, which are often prepared by condensation of bisphenols with n = 0 and epichlorohydrin. Typical compounds of this class are 4,4 '-(1-methylethylidene) diphenol, 4,4'-(1-methylethylidene) bis (2-methylphenol), 4,4 '-(1 -Methylethylidene) bis (2,6-dimethylphenol), 4,4 '-(1,1-cyclopentylidene) diphenol, 4,4'-(cyclohexylidene) diphenol, 4, 4 '-(1-methylethylidene) bis (2,6-dibromo phenol), 4,4'-methylenediphenol, 4,4'-(1-methylethylidene) bis (2-allyl Phenol), 4,4 '-(1-methylethylidene) bis (2-tert-butyl-5-methylphenol), 4,4'-(1-methylethylidene) bis (2-tert) -Butyl-5-methylphenol), 4,4 '-(1-methylpropylidene) bis (2-tert-butyl-5-ethylphenol), 4,4'-(1,4-bis (methyl) Diglycidyl ethers such as thilidene) phenyl) bis (2-tert-butyl-5-methylphenol), 4,4'-biphenol, hydroquinone, resorcinol and the like. In addition, oligomeric products produced during condensation reactions are known and useful. Examples of such compounds are bisphenol A and oligomeric condensation products of epichlorohydrin (n is 0.14), sold under the trade name EPON by the Shell Corporation under the trade name EPON 828.

2) The reaction product of the said diepoxide and bisphenol is collectively called improved resin. Typical examples include condensation products of bisphenol A diglycidyl ether and tetrabromobisphenol A. Partial condensation products suitable for use include a catalytic amount of a catalyst at a temperature of from about 50 ° C. to about 225 ° C., preferably from about 70 ° C. to about 200 ° C., and most preferably from about 100 ° C. to about 190 ° C., as described herein above. It can be prepared by heating a mixture of compounds in the presence of a metal salt with one or more basic reagents, such as copper (such as lithium dimethylgrate), amine, phosphine, or strong alkoxide counter ions.

Triarylphosphines, in particular triphenylphosphine, are effective basics in small amounts, have a low tendency for side reactions to occur, and are harmless when remaining after completion of the reaction, and thus are preferred basic reagents for bisphenol bisepoxide condensation reactions. Typically they are applied at about 0.1 to about 0.5 weight percent. Preferably, the reaction takes place in particular under an inert atmosphere such as nitrogen when triarylphosphine is used as catalyst. Aromatic hydrocarbon solvents such as toluene may also be used, but are not critical.

The partial condensation product may contain about 25% to about 35% brominated compound and about 15% to about 25% epoxidized novolak in balance with the unbrominated biphenol polyglycidyl ether. Low degree of condensation of the brominated compound or novolac can result in an unacceptable decrease in solvent resistance and / or flame retardancy. Increasing brominated compounds can produce incompatible materials. The preferred proportion of brominated compound is about 28% to about 32%.

3) Also, a multifunctional epoxide described in the following formula (6) may be used.

Materials described in formula (6) include all epoxidized phenolic resins, including epoxidized novolacs and resols. Wherein A ⁷ and A ⁸ are aromatic radicals unsubstituted or substituted with typical substituents selected from aryl, alkyl, alkoxy, halogen, and the like; The value of n is from 0 to about 500.

Examples of the most common compounds described in formula (6) include glycidyl ethers prepared by condensation of epichlorohydrin with phenolic resins. Examples of this class of compounds include phenol formaldehyde novolac, cresol formaldehyde novolac, bromophenol formaldehyde novolac, tert-butylphenol formaldehyde novolac, mixtures of phenols and dienes or dienes, such as dicyclopentadiene Or glycidyl ethers of phenolic resins derived from condensation reactions with butadiene, or additionally polybutadiene resins.

Other multifunctional epoxides include fluoroglucinol triglycidyl ether and tetrakis (glycidoxyphenyl) ethane.

4) Amine, amide, or nitrogen containing heterocycle glycidyl ethers. These substances include triglycidylcyanurate, triglycidyl isocyanurate, N, N, N ', N'-tetraglycidyldiaminodiphenylmethane, N, N, -O-triglycidyl-4 Aminophenols, N, N-diglycidyl aniline, and N, N-diglycidyl hydantoin.

5) Glycidyl ethers of carboxylic acids such as diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate and diglycidyl adipate.

6) Homopolymers or copolymers prepared from unsaturated epoxides such as glycidyl acrylate, glycidyl methacrylate and allyl glycidyl ether. As mentioned, these materials can be used as homopolymers or copolymers obtained from mixtures of the aforementioned unsaturated epoxides or from mixtures of unsaturated epoxides and other vinyl monomers known in carrying out vinyl polymerizations.

7) Polysiloxanes comprising glycidyl ethers of epoxy functional groups such as 1,3-bis (3-hydroxypropyl) tetramethyldisiloxane.

8) Compounds prepared by epoxidation of alkenes, dienes or polyenes, such as phenylglycidyl ether, allylglycidyl ether, naphthylglycidyl ether, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclo Hexane carboxylate, vinylcyclohexene dioxane and substituted derivatives thereof. In addition, epoxidized polyenes such as polybutadiene resins or butadiene comprising copolymers may be useful.

When the epoxide is a mixture, it is balanced with the unbrominated bisphenol polyglycidyl ether, typically about 30 to about 60% by weight of the brominated compound and about 5 to about 20% of the epoxidized novolac, if present Include.

Other useful thermosetting components are vinyl-based compounds such as triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl isophthalate, diallyl malate, diallyl fumarate, diethylene glycol diallylcarbonate, tri Allylphosphate, ethylene glycol diallyl ether, allyl ether of trimethylolpropane, partially allyl ether of pentaerythritol, diallyl sebacate, allylated novolac, allylated resol resin and / or cyanate esters. These various thermosetting resins can be used individually or in combination with each other.

Cyanate esters are most widely defined by the following general formula (7):

Where

A ⁹ is any aromatic, aliphatic, mixed aliphatic aromatic hydrocarbon, heterocycle or similar derivative thereof;

X is a cyanate group;

n is an integer of 1 to 10, preferably 1 to 4.

Typical compounds of this class are derived from the reaction of cyanogen halides with bisphenols described above. Examples of various cyanate esters can be found in "Chemistry and Technology of the Cynate Esters", I. Hamerton, Chapman Hall, 1994.

Polyimides, including bismaleimide, include those known in the art, such as those described in "Polyimides", D. Wilson, H. D. Stenzenberger and P. M. Hergenrother, Chapman Hall, 1990.

Phenolic resins include those known in the art as described in "Phenolic Resins: Chemistry, Applications and Performance", A. Knop, L. A. Pilato, Springer-Verlag, 1985.

Benzoxazines include those known in the art as described in US Pat. No. 5,973,144 to Ishida.

Polyurethanes include those known in the art as described in "Handbook of Thermoset Plastics", S. H. Goodman, Noyes Publications, 1986.

Examples of allyl-based, vinyl and silicone thermoset resins include those known in the art as described in "Handbook of Thermoset Plastic", S. H. Goodman, Noyes Publications, 1986.

Typically the thermosetting resin comprises about 50 to about 95 weight percent, preferably about 52 to about 80 weight percent, and most preferably about 55 to about 60 weight percent of the resin portion of the adhesive solid composition.

Reinforcing agents may be included in the composition to enhance the blending and crosslinking of the poly (arylene ether) and thermosetting resin portions of the adhesive composition. In general, the presence of a reinforcing agent reduces the fragility of the partially cured composition. In the final blend, the functionalized poly (arylene ether) is collectively referred to as "reinforced poly (arylene ether)" due to the improved compatibility between the poly (arylene ether) and other components. Thus, other reagents that affect the miscibility of poly (arylene ether) and various components of the blend (such as thermoset resins) are adjuvant. Miscibility includes stabilization of total phase separation between components of the blend. Indicative of improved miscibility, including, for example, increased softness and improved phase morphology stabilization. Improved miscibility of the blend component contributes to the desired physical properties of the adhesive.

Preferred reinforcing agents include polyvinyl butyral resins, including polyvinyl butyral and other vinyl monomers such as vinyl acetate, and derivatives thereof partially hydrolyzed. Examples of such materials are poly (vinyl butyral-co-polyvinyl alcohol-co-polyvinyl acetate). Particularly useful are polyvinyl butyral resins having a molecular weight of 50,000 to 120,000, which are commercially available from Solutia under the trade name, for example, BUTVAR. Other reinforcing agents include, for example, low molecular weight thermoplastic elastomers known in the art, such as styrene-butadiene-styrene (SBS) block copolymers, styrene-ethylene-styrene (SES) block copolymers, styrene-ethylene-butylene-styrene ( SEBS) block copolymers and functionalized butadiene-acrylonitrile copolymers such as B.F. Sold by the B. F. Goodrich Company under the trade name HYCAR® Reactive Liquid Rubber. Also included are reinforcements in the form of central sheaths, such as styrene-butadiene and styrene-butadiene core sheath rubbers. Other useful materials are described in "Rubber Technology Handbook", W. Hofmann & C. Hanser, Verlag Publishers (1989) and in "Chemistry and Technology of the Epoxy Resins", B. Ellis, Chapman Hall (1993) You can find it.

Typically used reinforcing agents consist of about 0.5 to about 15 weight percent, preferably about 3 to about 10 weight percent, and most preferably about 4 to 8 weight percent of the resin portion of the adhesive composition.

A curing agent is added to the composition to affect the crosslinking between the hydroxyl group of the poly (arylene ether) and the reactive thermosetting component. For the purposes of the present invention, the term "curing agent" is meant to include a curing catalyst and a promoter. Any known curing agent can be used. Suitable curing agents are described, for example, in "Chemistry and Technology of the Epoxy Resins", B. Ellis, Chapman Hall (1993). Examples of curing agents include amines, anhydrides, and carboxylates, such as metal carboxylates, wherein the metal is zinc, magnesium or aluminum; the carboxylates are C _1-24 carboxylates such as acetates, octoates or stearates. Included. Additional curing agents include imidazole and arylene polyamines, which are particularly suitable when the thermosetting resin is an epoxy resin. Typically the curing agent is present at about 0.1 to about 7 weight percent, preferably about 0.1 to about 1 weight percent, based on the total weight of the resin.

Optionally, plasticizers are used to make the partially cured substrates less fragile, as well as to reduce gelation and separation of the composition in solution. When used in suitable amounts, these plasticizers have a glass transition temperature of less than 1 ° C. for each poly (arylene ether) portion of the poly (arylene ether) without seriously affecting the glass transition temperature of the remaining thermosetting components. To decrease. Suitable plasticizers are known and include, for example, resorcinol diphosphate, bisphenol-A-diphosphate and isopropylated phenol phosphate. Plasticizers may be used from about 0 to about 20 weight percent, preferably from about 0.5 to about 10 weight percent, most preferably from about 1 to about 3 weight percent.

In addition, the adhesive composition may optionally include various adhesives such as antioxidants, ultraviolet absorbers, stabilizers such as light stabilizers and others, lubricants, pigments, dyes, colorants, antistatic agents, flame retardants, impact modifiers, and mixtures thereof. . Examples of antioxidants include organic phosphites such as tri (nonylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, bis (2,4-di-tert-butylphenyl) penta Erythritol diphosphite, 2,4-di-tert-butylphenyl phosphite, or distearyl pentaerythritol diphosphite; Alkylation reaction products of alkylated monophenols, polyphenols and polyphenols with dienes such as tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate)] methane and 3,5-di- Tert-butyl-4-hydroxyhydrocinnamate octadecyl; Butylation reaction products of para-cresol and dicyclopentadiene; Alkylated hydroquinones; Hydroxylated thiodiphenyl ethers; Alkylidene-bisphenols; Benzyl compounds; Esters of beta- (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid with mono or polyhydric alcohols; Esters of beta- (5-tert-butyl-4-hydroxy-3-methylphenyl) -propionic acid with mono or polyhydric alcohols; Esters of thioalkyl or thioaryl compounds such as distearylthiopropionate, dilaurylthiopropionate, ditridecylthiodipropionate; And amides of beta- (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid.

Flame retardant additives include both reactive and non-reactive flame retardants, such as derivatives of tetrabromo bisphenol A, such as bis (2-hydroxyethyl) ether of tetrabromobisphenol A, bis (3-acrylic of tetrabromobisphenol A Loyloxy-2-hydroxypropyl) ether, bis (3-methacryloyloxy-2-hydroxypropyl) ether of tetrabromobisphenol A, bis (3-hydroxypropyl) of tetrabromobisphenol A Ether, bis (2,3-dibromopropyl) ether of tetrabromobisphenol A, diallyl ether of tetrabromobisphenol A, and bis (vinylbenzyl) ether of tetrabromobisphenol A, pentabromobenzylacrylic Rate; Dibromostyrene; Tribromostyrene; Tetrabromocyclooctane; Dibromoethyldibromocyclohexane, such as 1,2-dibromo-4- (1,2-dibromoethyl) -cyclohexane; Ethylene-bis-tetrabromophthalimide; Hexabromocyclododecane; Tetrabromophthalic anhydride; Brominated diphenyl ethers such as decabromodiphenyl ether; Poly (2,6-dibromophenylene ether); And tris (2,4,6-tribromophenoxy-1,3,5-triazine; and phosphorus-containing additives such as those described above and in the "Plastic Additives Handbook", 4 ^th Edition, R. Gachter and H. Muller (eds.), PP Klemchuck (assoc, ed.), Hansen Publishers, (1993)] Typically, such additives comprise from about 12% to about 20% by weight of the bromination additive. Or at a concentration of about 15 to 25% by weight of the phosphorus-containing additive, in addition, flame retardants include brominated thermosetting resins such as brominated poly (epoxides) or poly (arylene ethers) having phosphorus-containing moieties in the backbone. It may also be dispensed with the composition.

If a flame retardant is used, it is preferably present in an amount effective to achieve a V-1 rate, more preferably a V-0 rate, as measured by our laboratory test procedure UL 94. The V-0 rate requires a FOT of 50 seconds or less in combination for five samples with a burning time (FOT) of 10 seconds or less in any test.

In addition, other known as described, for example, in "Plastic Additives Handbook", 4 ^th Edition, R. Gachter and H. Muller (eds.), PP Klemchuck (assoc, ed.), Hansen Publishers, (1993) Modifiers, fillers, antioxidants, ultraviolet absorbers, stabilizers, lubricants, plasticizers, pigments, dyes, colorants, antistatic agents and flame retardants may also be used in the present invention.

Fillers may also be optionally added to the adhesive composition for the purpose of adjusting the dielectric constant, loss factor and expansion properties consistent with the adhesive. Suitable fillers include, but are not necessarily limited to, silicates, titanium dioxide, fibers, glass fibers (including continuous fibers and occluded fibers), carbon black, graphite, calcium carbonate, talc and mica. Suitable fillers are determined by the desired desired product.

Typically, the preparation of the adhesive composition can be accomplished by simply blending the components under conditions suitable for forming the intrinsic blend. In addition, nonreactive solvents such as hydrocarbons such as toluene or xylene can also be used. During mixing, the blend is preferably heated sufficiently so that the components mix well in solution. These conditions include that the mixed components in the container capable of heating and shearing action are completely dissolved and all components are blended.

Suitable adhesives are metals, in particular conductive metals such as copper or aluminum, and dendritic thermoplastic base materials, in particular those known for printed circuit boards such as polyimide, polyetherimide, and polyesteretherimide polymers, and poly (arylene ether) And blends of polyimide or polyester polymers. Many poly (arylene ether) compositions having desirable dielectric properties and their use in the manufacture of circuit boards are known.

In use, the adhesive composition is blended and then applied to the adhesive in a known manner, including by spraying, dipping and various known roll transfer preparation methods. If present, the solvent is removed and the adhesive composition is partially cured. In general, it is necessary to heat for at least about 2.5 hours at a temperature above about 180 ° C. to fully cure. Less cured may be used depending on the nature of the desired final product.

In a typical process for making rigid metal coating materials using poly (arylene ether) compositions, individual laminas (collectively referred to as “prepregs”) are prepared from dendritic binder compositions. The continuous reinforcing web can be pre-impregnated with the solution and then dried in a vertical or horizontal treatment tower or oven. Usually, the resin is present in the tower or oven processor and then partially cured or B-staged. A metal, typically copper, foil coated with the adhesive composition is placed on one side of the prepreg and heated under pressure to cause bonding between the metal foil and the substrate. Multiple prepregs can be used to form a single composition plate. In addition, the multilayer printed wiring board can have multiple overlapping lamina and copper sheets. The curing cycle in the compactor depends on the nature and thickness of the laminate, the time and temperature of the cycle required to cure the substrate and the bonded prepreg layer. Sufficient pressure is required to effect proper flow of the base resin for proper dehumidification and bonding of the fabric base. The pressure should be sufficient to prevent foaming due to the release of volatiles retained in the substrate or adhesive layer, or gases generated from the product during the curing process.

In a typical procedure for producing a flexible metal cladding plate using the present adhesive composition, individual laminas are prepared from a film, such as a polyimide film such as those sold under the trademark KAPTON® by DuPont. . The metallized thermoplastic film is coated with the adhesive composition on the nonmetal side, and the adhesive side of the composition is placed in a prefabricated inner layer of the circuit and then heated under pressure to bond between the thermoplastic substrate and the inner layer of the circuit. Typically, the cured adhesive layer is about 0.5 to about 2.5 mils thick. Thermoplastics multimetalized with an adhesive can be used to make a single composite plate. In addition, the multilayer printed wiring board can have multiple overlapping lamina and copper sheets. The cure cycle in compression again depends on the nature and thickness of the laminate, the time and temperature of the cycle required to cure the substrate, and the adhesive layer bonded. Sufficient pressure is required to effect proper flow of the adhesive and / or base resin for proper dehumidification and bonding. The pressure should be sufficient to prevent foaming due to the release of volatiles retained in the substrate or adhesive layer, or gases resulting from the product of the curing process.

For example, the adhesive layer can typically provide a thickness of about 0.0005 inches to about 0.003 inches, and the adhesive can typically be cured at a temperature of about 175 ° C to about 205 ° C. The specific combination of resin thickness, curing time and curing temperature can be selected by various factors, and are not limited to the specific form of the resin used and the specific use. Those skilled in the art will know how to select the specific cure time and temperature required to provide adequate dielectric constant for the final circuit board.

The resulting circuit board is then capable of further processing such as producing very thin circuit traces due to the smooth surface of the thin copper and thermoplastic films. These circuit board manufacturing techniques are known in the art. Thermoplastic / adhesive compositions are completely organic in nature and are completely corrosion removable with a laser for drilling, and are useful for example in microbias technology.

The invention is further illustrated by the following examples, but is not limited thereto.

Example

The components used in the examples below are shown in Table 1 below. The poly (arylene ether) named "PPO® (0.30 I.V.)" is not commercially available and was prepared and isolated according to known techniques for the oxidative bonding of 2,6-xyleneol. Similar synthetic procedures are described, for example, in US Pat. No. 3,306,875 to Hay.

Trade name source ingredient PPO® (0.40 I.V.) General Electric Poly (arylene ether), I.V = 0.40, number average molecular weight = 14,200 PPO® (0.30 I.V.) General Electric (Vichy) Poly (arylene ether), I.V = 0.30, number average molecular weight = 11,000 Bisphenol A-157 Shell chemical Bisphenol A 75% dibenzoyl peroxide, hydrated Lucidol Benzoyl peroxide EPON (registered trademark) 1163T60 Shell chemical Brominated epoxy resin Improvement resin General Electric EPON® 828 / TBBPA Copolymer ARALDITE® EPN1138 Ciba Geigy Epoxy novolac Bootbar (registered trademark) B76 Solutia Polyvinyl butyral Kraton (KRATON; registered trademark) D1101 Shell chemical SBS Block Copolymer Term-check (THERM-CHEK) 705 Ferro Corporation Zinc Octoate ETHACURE (registered trademark) 100 Albemarle Aryl amine Imikur (registered trademark) EMI-24 curing agent Air Products Imidazole accelerator - General Electric Resorcinol Diphosphate (Plasticizer) KAPTON (registered trademark) -0.002 " DuPont Polyimide film GOULDFLEX®-0.002 "PI Good Electronics Metallized polyimide film

Poly (arylene ether) -epoxide adhesive compositions were prepared having a composition as outlined in Table 2 below. First, poly (arylene ether) was dissolved in toluene and tetrabromobisphenol-A diglycidyl ether to prepare a solution containing about 40% solids. The solution was heated to 90 ° C. to 100 ° C., then bisphenol A and benzoyl peroxide (or benzoyl peroxide alone) were added and held at 90 ° C. to 100 ° C. for about 90 minutes. The solution was cooled and styrene-butadiene-styrene (SBS) block copolymer or polyvinyl butyral admixture was added. Another epoxy resin (bisphenol-A diglycidyl ether / tetrabromo bisphenol-A condensation product and epoxidized novolac) was added and the amount of toluene was adjusted to produce a resin solution with 50% by weight solids. The formulation was then completed by adding a curing agent package consisting of zinc octoate, 2-methyl-4-ethylimidazole, and diaminodiethylbenzene.

Polyimides coated with each resin solution are described. Drawdown bars (# 12-# 30) were used to apply the solution to the substrate at different thicknesses. Each coated material was heated until the solvent and partially cured resin were removed to produce a B-staged coated thermoplastic. A glossy smooth drum face of 1 ounce of copper foil (available from Good Electronics) was laminated to the adhesive coated thermoplastic. Typical lamination cycles were 200 lb (pounds) and 190 ° C. per square inch (psi) for 3 hours.

The physical properties were determined for each cured composite material and the results are listed in Table 2 below. The amount of each component shown is the weight percent of the solid composition. All measurements were made at room temperature unless otherwise indicated. Z-axis expansion was measured according to IPC-TM-650 2.4.24. Pill A and the pill after soldering were measured according to IPC-TM-650 2.4.8. Soldering time was measured according to IPC-TM-650 2.4.13.1. A three hour pressure instrument test was measured according to IPC-TM-650 2.6.16.

The solid resin rod produced for this purpose was a solder immersion sample.

ingredient One 2 3 4 5 6 PPO (I.V. = 0.40) 31.89 30.46 30.37 30.18 - 29.15 PPO (I.V. = 0.40) - - - - 30.65 - Diglycidyl ether of tetrabromobisphenol A 32.56 31.1 31.0 30.82 31.29 29.76 Bisphenol A 0.32 0.30 0.31 0.30 - 0.29 Benzoyl peroxide 0.32 0.32 0.32 0.31 - 0.30 Epoxy novolac 14.68 14.0 13.98 13.90 14.11 13.42 EPON828 / TBBPA Copolymer 14.68 14.0 13.98 13.90 14.11 13.42 Polyvinyl butyral - 4.48 4.47 4.44 4.51 - SBS Block Copolymer - - - - - 8.58 Zinc Octoate 4.25 4.06 4.04 4.02 4.08 3.88 Diethylenediamine 0.93 0.89 0.89 0.88 0.90 0.85 2-methyl-4-ethyl-imidazole 0.36 0.35 0.35 0.35 0.35 0.33 Plasticizer - - 0.30 0.91 - - Property Glass transition temperature T _g (℃) 149/197 130/185 133/192 126/165 137/196 141/177 Z-axis expansion (30-260C,%, clean resin rod) - 4.18 4.37 4.48 - - Film thickness (in) 0.002 0.002 0.002 0.002 0.002 0.002 Fill A (lbs / in) 5.9 6.6 7.0 7.6 6.6 8.0 Post Soldering Fill (lbs / in) 4.6 6.1 5.8 8.1 5.8 8.3 2 minutes immersion by soldering at 288 ℃ no effect no effect no effect no effect no effect no effect Soldering Time (sec) - - 80-120 126-155 100-205 181-272 3 hour pressure apparatus Pass Pass Pass Pass - -

It should be noted that the peel failure mechanism for all samples can be found in the cohesion failure between copper and adhesive rather than adhesive and thermoplastic. High bond strength between the adhesive and the thermoplastic is desirable for reliability.

While preferred embodiments have been shown and described, various modifications and substitutions can be made without departing from the spirit and scope of the invention. Accordingly, it should be understood that the present invention is described by way of example and not limitation.

All cited patents and other documents are incorporated herein by reference.

In accordance with the present invention it is possible to obtain adhesives for thermoplastic films which are particularly useful for printed circuit boards from compositions comprising blends of specific compositions consisting of poly (arylene ether) resins, thermosetting resins, reinforcing agents, curing agents and optional plasticizers.

Claims (17)

Based on 100% by weight of the resin portion of the composition, Poly (arylene ether) resin having a number average molecular weight of about 5 to about 50 weight percent of about 8,000 to about 13,000; About 50 to about 90 weight percent of a thermosetting resin; About 0.5 to about 15 weight percent of an adjuvant; And About 0.1 to about 7 weight percent of a curing agent Adhesive prepared from a composition comprising a. The method of claim 1, The adhesive selected from the group consisting of cyanate esters, polyesters, epoxies, benzoxazines, benzocyclobutene resins, and mixtures comprising one or more of these thermosetting resins. The method of claim 2, And the thermosetting resin is an epoxy resin comprising a condensation product of bisphenol polyglycidyl ether and bromine substituted bisphenol. The method of claim 2, Epoxy is a reaction product of tetrabromobisphenol A and diglycidyl ether of bisphenol A or bisphenol F, an average of not more than one aliphatic hydroxy group reaction product per molecule, and about 10 to about 30 weights as aryl substituent Adhesive which is a reaction product comprising% bromine. The method of claim 2, Adhesives wherein at least one halogen-free epoxidized novolac is present. The method of claim 1, Adhesive wherein the thermosetting resin comprises an epoxy and a cyanate ester. The method of claim 1, Wherein the thermosetting resin comprises a cyanate ester and an epoxy comprising a condensation product of bisphenol polyglycidyl ether and bromine substituted bisphenol. The method of claim 1, The adhesive whose reinforcing agent is polyvinyl butyral. The method of claim 8, The adhesive wherein polyvinyl butyral is present at 1-15% by weight of the total solid composition. The method of claim 8, The adhesive wherein the reinforcing agent is styrene-butadiene-styrene block copolymer. The method of claim 1, An adhesive further comprising a plasticizer effective for the poly (arylene ether) polymer. The method of claim 11, And the plasticizer is resorcinol diphosphate, bisphenol A diphosphate or isopropylated phenol phosphate. The method of claim 1, An adhesive further comprising at least one selected from the group consisting of denaturing agents, fillers, antioxidants, ultraviolet absorbers, stabilizers, lubricants, plasticizers, pigments, dyes, colorants, antistatic agents and flame retardants. The method of claim 1, About 20 to about 40 weight percent poly (arylene ether) resin; About 52 to about 80 weight percent of a thermosetting resin; About 3 to about 10 weight percent of an adjuvant; And about 0.1 to about 7 weight percent of a curing agent. Based on 100% by weight of the resin portion of the composition, About 5 to about 50 weight percent poly (arylene ether) resin, wherein the poly (arylene ether) resin has a number average molecular weight of about 8,000 to about 13,000, and includes a high molecular weight poly (arylene ether) and a peroxide, and Optionally, a reaction product of a phenolic compound); About 50 to about 90 weight percent of a thermosetting resin; About 0.5 to about 15 weight percent of an adjuvant; And About 0.1 to about 7 weight percent of a curing agent Adhesive prepared from a composition comprising a. Thermoplastic substrates; A thermally conductive metal foil located at least partially on at least one side of the substrate; And An adhesive located between the substrate and the metal foil, wherein the adhesive is a poly (arylene ether) resin having a number average molecular weight of about 8,000 to about 13,000 of about 5 to about 50 weight percent based on 100 weight percent of the resin portion of the composition From about 50 to about 90 weight percent of a thermosetting resin; from about 0.5 to about 15 weight percent of a reinforcing agent; and from about 0.1 to about 7 weight percent of a curing agent) Laminate comprising a. Based on 100% by weight of the resin portion of the composition, Poly (arylene ether) resin having a number average molecular weight of about 5 to about 50 weight percent of about 8,000 to about 13,000; About 50 to about 90 weight percent of a thermosetting resin; And About 0.1 to about 7 weight percent of a curing agent Adhesive prepared from a composition comprising a.